Kouris, S. S. “The Solar-Cycle Variation of M(3000)F2 and Its Correlation With That of f0F2”. Annals of Geophysics 41, no. 4 (November 25, 1998). Accessed May 21, 2022. https://www.annalsofgeophysics.eu/index.php/annals/article/view/3804.